The present invention relates to an exposure system for use in a camera provided with an auxiliary light for carrying out proper photography and, more particularly, to an exposure system which has a greater choice of combinations of the exposure mode and the mode of flash light produced from the auxiliary light than that of conventional exposure systems.
Conventionally, there have been proposed three different exposure systems for carrying out photography using a flash light with an automatic control of flash light intensity or of aperture size of the camera. The first system is a type in which the aperture size is automatically controlled relative to the change of camera-to-object distance with a flash light apparatus producing a constant intensity of flash light. This first system is called Flash'o-matic. The second system is a type in which the light intensity of the flash light is automatically controlled relative to the camera-to-object distance and relative to the reflectance of the object to be photographed with the aperture being set to a predetermined size. The third system is a type in which the light intensity of the flash light is automatically controlled relative to the camera-to-object distance and relative to the reflectance of the object with the use of the measured value of reflected light on the light-sensitive film and the aperture being set to any desired size.
Although the first system has an advantage in that it is not necessary to take the reflectance of the object into consideration, the aperture size of the camera is limited within a fixed range and, therefore, limiting the available range of distance in which the object to be photographed can be located. The second system has an advantage in that it is possible to take a photograph of an object which is located very close to the camera; it has, however, a disadvantage in that the fixed aperture size provides no desired depth of field, particularly when taking a photograph of an object which is located close to the camera and has a further disadvantage in that it is necessary to take the reflectance of the object into consideration. The third system also has, in addition to the necessity of taking the reflectance of object into consideration, a disadvantage in that the reflectance of the film itself serves as one element to cause errors in the exposure adjustment.